Batten no Yu is a natural hot-spring super sento near Ezu Lake in Higashi ward, run by the Kumamoto Spa Resort Group. Its main bath has nine kinds of hot-spring bath and a jacuzzi, with 15 private family baths in the main building and the Manyokan annex. Sauna-listing sites record a sauna and cold bath in both the men's and women's sides. Adult entry is ¥750, or ¥550 if you bring your own shampoo. Open daily 10 AM to 2 AM.